SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '40049232ae816bb638504b0724f6377df173ef09cadf76a0b431ba7232453626' 
  AND token = 'RhLUaiZvxmipDsofVi+WX8GOjTVV2NpYWdT1/14BYmc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}